Lithographer&#39;s plate-holding mechanism.



vJ. D.-MCRACKEN.

LnHoGnAPHEHsPLATE HOLDING MEcHANlsM.

APPLICATIONYQILED DEC. I3. I9l6. y

Patented Dec. 3, 198.

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- 1{grilli/ins DQ'iyIcoaAcg/EN, 0F :iriver-ignari), orrid. issn-moa Tonia-E NrTnD sfmrrrzsfk Y l PrAYnve cAIm cci/rang or cinoINNArI, forno, n coRroaATIoN. oF omo,

rr'rrr'oennrnuns ignara-nonnina MECHANISM.

4 TonZZ whoml'l't concern? j: jy;

f Belitknown that l, JAMEsD, MeRciEN,

a citizen-0f the United- States.;7 and residing atA Cincinnati, the/.county of Hamilton 4State of .Oh'io,have invented 'a ,new

`and-useful Improvement in Lithographers Plate-Holding Mechanism, of which the yfollowing specification is a `full disclosure.

Myinvention relates toan improvement in 4mechanism for holding a lithographing platefuponthe support Aof a rprinting press',

such as a cylinder or= flat bed. 1-

The invention istl illustrated in its, preferred form as applied to, the cylinder of av lithographie press.. of the offsetv typeand it is shownin thisusage because the problemy Y, of holding and adjusting a `thin shell or lithograpers plate upon a curved surface4 presents vdifficult mechanical conditionsA 'not incident tovfiat beds, although the, invention 4constitutes a useful improvement-inl this relation also.v .Y

The object of the invention `will be best ylar lithographie problem involved.

.In lithography work, such as two or morer color. printing, or say, in the. work of print,

ing 'playing cards, it is necessary that the successive prints from a given plate register' thevface ofthefljcard; have to Valways be in the same relationship, to one another so asy to register .accurately and invariably with the printing ofi the backs .of the*l cardsl `In very .delicate'work of thissort slight irregularitymay, be serious in practice. Ow-

ing tothe flexibility of' paper, and. possibly,

also, becausefofitsyliability to shrink; it

happensl thatlgin the work of running the paperfthrough the presses, the paper-will stretch morein s'omeinstances than it will in others5 rfthat a givenpiece of paper will: stretchmore along one edge in a direction.'

circumferential of the-cylindery than i' on 'the otheredge.A t

, Ity isJ the' obj ect'of'my invention lto provide a holdingmechanism for" the edge of a plate whichj .will securely hold the AYplate/down upon: therlcurved cylinder surface, butjy iny whicha portion of the clamping-edge1nay` l the left handy edge of. aprint -is'flexed say understood by brief mention of theparticu--V t* "Fig 2 is a section on line 2-2, Fig l.

So also, in making playing.

j j siieiiiafitiib'f Letters-iraient; yj1 glt1j'"159d1)@ 31918 '.ApplicationfuaDecember'13,1916. serialNo; 136,702.

be adjusted circumferentially inirelation to anotherclamped `-portion-l ofthe edge ofthe printingjplate;which: is heldstationarfy.l lIn vother words; iff say, onl fa givenn job.

one-sixteenthy of an inch -inu a'fdifrection circumferential ofthe-cylinder' more than `therl right" hand edge, thistcan be correctedV by 'i' adjusting the appropriate. platefholding de'- vices tosdraw the. right-v handfedge'oftheplate the needed one-sixteenth 4.ofI an inchl overthe fcylinder to vcompensate'for the dimensionr-.of'paperzstretchingat the left hand edge of the printing`l plate. i Preferably thel printing surface is divided 'into separably adjustable circumferential plate'sections, enabling a. realinem'enttorv be made through fthe adjusting mechanism to v correct nonregistration. 'l

The features ofthe invention will bemore fully set forth inl` the description of the acf -companying drawings, forming apart of this specification, inv which y u Figure l'v is a plan -view of acylinder showing the holding mechanism.

`3 vis an enlarged detail vertical "sectional view-throughfone of thel adjustable plate-holders on line '3e-3, Fig. l'. j c' ,Y

The form of cylinder l, shown, is conventional. A portion of theI cylinderl is broken away to form the recess'Q for the fixed clampingv mechanism', and another portion broken away to formfthe recessBQ i U for the adjustable plate holding mechanism,

v,positioning the plate-holding devices'at op-.-V

posite end'sxof' a'ndf'belowl the support'surfacey .for the printingfpiat.:

t The recess portion l 3 1 is formed with a ,fiat y "or seat surface f4; 'enabling ythe adjustment -of lthe plate-holderfin Va straight line,and c the recess end nearest they cylinder' 'surface` is gfomedfto 'constitute' shoulder or abut-l' ment 5 extending clear across the. cylinder in' a `direction parallel to the axis? 'In the r'ece'ssz2 isa pivot or fulcrumrod secured between the cylinder heads? Aand fulcrum'eduponfthisrodare a series of*V yoke warms. 8- having clampingl` l.jaws 9. formed at their outerends, whichjaws are opened andV close'dby ascrew clamp l0, `and these yoke'.vl arms are strained by means ofv adjusting bolts `11; the'fends of which bear against 'the v radialfwebflQ-gwhich defines one wallof thel recess 2.!

The adjutabipiatehblaing embers are', positioned in the recess 3 and seated uponthe flat` surface 4 l so?" as 'to be "sli'dablef thereon.

These faeljustable'l plate'5holders 'comprise series of transverselyv elongated basernern bers 13,114, l5,y 16, seatejdon 'the' slide-way 4 and secured thereto by bolts `17 ,.there be;

' ing-"two `-.such bolts fori each of "said base members.v The vrbase members. arel formedv with slightly y.enlarged .apertures 1 8 for said bolts i117, enablingYV :the bases to Vbe moved on i the seat tofor fromshoulder 5,1or' angula'rly f c thereto, w the'. #bases "extending preferably i hearlyythezfull .length ofl the''seat andgbelng y 'La narrower in `widththan thefseat; v y These base members constitute,"the-.bottom bers to tightly grasp one edge' ofrthe printf ingv plate and :this clamp is1 effected :by the bolt 27fw'hich passes 'throughfa rear portion of thetop member, its linner en'djdownwardly abutting a surface ofthe-lowerbasef for i,exerting aclamping o r grippingjstram on a plate edge,' .and,secur1ngit, irml-yvupon' the base, l, ufl] l f lhe bases are "adjusted 'on the seat 4by means of'bolts28, 29, which .extend through" the bases and abutagainst the shoulder 5,-

afterfwhich they areclam'ped in anadjusted positionqon theseat byqbolts 17. .Oneedge of the platevBO is clamped .be-c'V tweenthe jaws 9 and thebolts11 areqtightvcned up -to properly set land hold-this endofvk the plate-.in relation to,thecylinderi-fy -f relation to "a Isingle AplateeXtending substan'- tlally across. the cylinderfrom endlitok end,f`lv

' have found ythat Ait-is5particularly useful'in t to relationtoa unitary plate whichisfpdivided up, as indicated by @lines l ,w,ju'1",.ft, so as' to.

constitute separable circumferential lsectionsf of What maybe regarded as ya unitary plate: j

or 'printing/i surface.

` Theother end of base members 13,1, 14 .15g-16,and the-top members 19, and normally, or injistarting,the?,v .,bolts28z, 29,* are tightened' up tostretchthef' plate uniformly around :the cylin'der; and it will .be assumed that 1in this normal ,jorY ini-, 'tiall position, 4 these c bases are; all; substantially alined on the seat4. c l

. vAs prints are runy off from-vtheicylinden they are@ from timel to time matched: 'with*-a-A test print and notations taken to deteettnyg .liable tobuckle or bend the'}; l-ate. ff v' This vcharact'eristic will be? f nd'ars'tood for 5 .'ins'tance'frcm the fact that alllof these adjustments take'Y placemV thepflat or :plane-y *A seat-,surface 4,.' and'y that f? i'trfis!y allacconfrlplished ythrough *movements f ofthese-f` bases 13,114, 15, .16, oni this flat seat;theginove-y ments being eithervfacgbodily lrn'ovenient inf'; .orl outiof one ofthe entireubase,-orfa slight' swiveling of one f of ,theseelongatedy basesfonV :flhe-.flat f seat V4 l extends f line" ltransp' "i verse to the cylinder axis, c and so 'provides' va:linealadjustment for .o'ne'setf of 'clamps, transverse-tothe cylinder axis; The fangulalrftios, teferrect which the plate h ning basees'hafve to `be prop ely regg@ O" "ofthese vba's'esm'ay be dawnilnrelae .tiontotheotherpthat,is, drawn outv of the initialVL al1nein'ent,'iependmg upon where the correctionjs to befmade or ajcorrectionocanf i c b e Yfm'ade'by adJustlng one end 'of'agrven -base inifrelationatoits other end, yas byre-r laXing the boltsl?, andadjusting one orthe' other/of thebolts`28,"'29;wherehy `thatfendof the-jaw -errespondmg to the bolt 'adjusted 'in'ovesrin the arc of acirclein relation'fto`y fixed', `that is toy say, thef 'non-adjusted bolt- 28 or 29 serves as'the center off this 'adjustingv movement. l

2"s'hould bef slightly relaxed 'atzthe'-proper.

place, Aunti'l the ibase' members in re'ces'si" Iareli repositioned, and thenV the Jme'mbersain recess'f..

2 are againl tightened "upf "is4V to? say,

when, as in the preferred form, the. plate? is 1 separable, 'or y 'divided *in 'circumferential lines,one of these sections" nof the printingfplate, say the medial section,"can befcircurn ferentiallyladjusted*in relation `t'olrthe fixed section of fthe plate, say f the' end section-s", or vice versaw" It VWin .be readily Stif-that; thgfialechanism' provides very delicatel and 'yet"f "v'ery`, precise means for-'making' ci'rcu'infer'en'tial` adjustments of oney portion# of ai printing plate in relation toy ianotherfinfthe direction; endwise of thel'cylinder, and at "ithe `same time @that the plate is securelyv heldfuponvl i the supportingI surface. (Drdinarily such la printing' plate is a thinlmeta'llic shell; and y' te'adjust one portion thereof:infzrelationfto 'While c h invention' m y-be utilized-Jin; A 'i another, the clamping0r"fadj usting,strains i provided for correcting all kinds of irregularity in the printing surface, and for truing the plate on the cylinder surface. I claim l. In a device of the class described, a printing plate support, means at one end of the support and below thek supporting surface for gripping the plate and holding it down on the support, a plurality of bases' at the other end of the supporting surface independently adjustable lineally and pivotally in relation to the support, and means for clamping the edge of the plate upon said bases.

2. In a device vof the class described, a printing plate support, means at one end of the support for holding the edge of the plate upon saidsupport, a flat seat at the other end of the support extending transversely of the support and below the level of the support surface, al seriesQ of bases on said seat extending transversely to the support, and independently adjustable lineally and pivotally on the seat, means for clamping the bases upon the seat in adjusted position, and means for clamping a plate edge upon said bases.

3. In a device of the class described, a printing plate support, a seat formed at one end of the' support below the supporting surface, said seat extending transversely to the axis of the cylinder, a series of bases on the seat independently movable bodily or angularly upon the seat, means for clamping the bases independently on the seat in adjusted position and means on each vbase for securin a plate edge thereto.

4. In a evice of the class described, a cylindrical supportsurface for a printing plate, a printing plate separable circumferentially, means for clamping a plate edge at one end ofthe support, a seat surface at the other end of and depressed relative to 'said support, lplate section holding members independently adjustable lineally and angularly on said seat surface, and means for securing each `of said members in adjusted position in relation to the end of the suport. Y p 5. In a device of the class described, a cylindrical supporting surface for a printing plate, means for gripping the plate edge at one end of thesupport, a dat seat and a shoulder formed at the other end ofthe Copies of this patent may be obtained for support, a series of bases independently adjustable on said seat, screw members passing through said bases parallel with the seat and abutting the shoulder'for effecting the adjustment, means for clamping each of the bases on the seat in adjusted position, and means on each base for gripping a plate edge.

6. In a device of the class described, a printing plate support, means carried by said support for securing one edge of a printing plate and an adjustable device carried by said support for clamping the opposite edge of said plate, said device being adjustable in a linear direction and in circular directions about an axis perpendicular to the plane of linear adjustment.

7. In a device of the class described, a printing plate support, means carried by said support for securing one edge of a printingplate, a dat seat on said support, a

series of clamping devices mounted upon said seat in surface engagement therewith, said clamping devices being independently adjustable on said seat in linear directions and in' circular directions in planes parallel with said seat and means for adjusting said clamping devices.

f 8. A printing cylinder having a first peripheral depression, plate chains secured thereon, and a second peripheral depression providing a flat seat extending as a section of a chord in relation to the cylinder, and a shoulder perpendicular to said seat, plate chains adjustable lineally on said seat and yalso angularlyadjustable on said seat.

JAMES D. MCCRACKEN. Witnesses:

CLARENCE B. FOSTER, LomsE BECK.

f witnesses.

ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

